Implantable vital sign sensor

ABSTRACT

An implantable vital sign sensor including a housing including a first portion, the first portion defining a first open end, a second open end opposite the first end, and a lumen there through, the first portion being sized to be implanted substantially entirely within the blood vessel wall of the patient. A sensor module configured to measure a blood vessel blood pressure waveform is included, the sensor module having a proximal portion and a distal portion, the distal portion being insertable within the lumen and the proximal portion extending outward from the first open end.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation-in-Part application of U.S. patentapplication Ser. No. 15/083,676, filed Mar. 29, 2016 entitled“IMPLANTABLE VITAL SIGN SENSOR”, which is related to and claims priorityto U.S. Provisional Patent Application Ser. No. 62/143,592, filed Apr.6, 2015, entitled “IMPLANTABLE VITAL SIGN SENSOR”, and is also relatedto and claims priority to U.S. Provisional Patent Application Ser. No.62/168,754, filed May 30, 2015, entitled “IMPLANTABLE VITAL SIGNSENSOR”, and is also related to and claims priority to U.S. ProvisionalApplication Ser. No. 62/256,476, filed Nov. 17, 2015, entitled “OPTICALMETHODS FOR MEASURING PRESSURE LONG TERM TO DETECT AND MONITOR PRESSUREVARIATIONS AND WAVEFORMS”, the entire contents of each of which arehereby incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD

An implantable vital signs sensor and method of implantation thereof.

BACKGROUND

Real-time monitoring of a non-ambulatory patient's vital signs istypically achieved through non-invasive methods. For example, a patientin an operating room or ICU bed may have a blood pressure monitor with acuff disposable about the upper arm; a pulse oximeter engaged around afingertip; adhesive electrodes affixed to the skin (proximate to theheart) that measure the electrocardiogram and respiratory rate/patternof respiration; an oral/aural thermometer that measures bodytemperature, and a stethoscope for monitoring heart/lung/airway sounds.These non-invasive vital signs sensors are often cumbersome andunwieldy. Patients that are hospitalized, immobilized, or stationarycommonly tolerate the inconveniences inherent in non-invasive sensors.

The real-time monitoring of an ambulatory patient's vital signs,however, is more challenging owing to the patient's mobility, and lackof supervision by hospital staff. Many patients are not compliantobtaining frequent or timely vital sign measurement using non-invasivesensors. Moreover, even when a patient is attentive to compliance, thecumbersome nature of such devices often results in patient's eitherremoving the devices or shifting the devices to a more comfortableposition, which can create artifacts, inaccurate readings, and occludeblood flow. Moreover, non-invasive devices are typically less accurateand less stable than implantable sensors.

Long-term implantable intravascular blood pressure sensors have beendevised to measure blood pressure in real-time. However, suchintravascular blood pressure sensors are prone to obstruct blood flowand cause endothelial cell injury, thrombosis, and emboli. Otherlong-term implantable blood pressure sensors are disposed around theouter diameter of an artery wall and use applanation to produce a robustmechanical coupling with the transducer's diaphragm. Still otherimplantable blood pressure sensors are used for short periods of time inthe operating rooms, catheterization laboratories, and ICUs of ahospital.

SUMMARY

An implantable vital sign sensor including a housing including a firstportion, the first portion defining a first open end, a second open endopposite the first end, and a lumen there through, the first portionbeing sized to be implanted substantially entirely within the bloodvessel wall of the patient. A sensor module configured to measure ablood vessel blood pressure waveform is included, the sensor modulehaving a proximal portion and a distal portion, the distal portion beinginsertable within the lumen and the proximal portion extending outwardfrom the first open end.

In another embodiment, a method of implanting a vital sign sensorincludes percutaneously advancing a blood vessel piercing element. Theblood vessel wall is pierced with the blood vessel piercing element andthe blood vessel piercing element is advanced to at least one of aposition adjacent and proximal to the basement membrane and to aposition through the basement wall to create a cavity therein. A housingis slid over the blood vessel piercing element and positioned within thecavity, the housing defines a lumen there though. A sensor module isinserted within the lumen of the housing, the sensor module beingconfigured to measure a blood vessel blood pressure waveform.

In yet another embodiment, the implantable vital sign sensor includes anelongate and biodegradable housing including a first portion, the firstportion defining a first open end, a second open end opposite the firstend, and a lumen there through, the first portion being sized to beimplanted substantially entirely within the arterial wall of thepatient. A second portion is substantially orthogonal with the firstportion and configured to contour an exterior surface of the arterialwall when the distal end of the first portion is inserted to a positionwithin the arterial wall substantially co-planar to the basementmembrane and endothelial cells of the arterial wall. A sensor moduleretainable within the first portion is included, the sensor modulehaving a pressure transducer configured to measure an arterial bloodpressure waveform, the sensor module having a deflectable diaphragmresponsive to a blood pressure waveform within the artery, the diaphragmbeing substantially co-planar to the basement membrane and endothelialcells of the arterial wall when the sensor module is retained within thefirst portion.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, may be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 is a front cross-sectional view of an embodiment of implantablesensor constructed in accordance with the principles of the presentinvention;

FIG. 2 is a front cross-sectional view of the implantable sensor shownin FIG. 1 implanted within a blood vessel wall;

FIG. 3A is a side view of the implantable sensor shown in FIG. 2;

FIG. 3B is a front cross-sectional view of the implantable sensor shownin FIG. 3A;

FIG. 4 is a front cross-sectional view of the implantable sensor shownin FIG. 1 with an outer flexible stent or fabric that holds the sensoragainst the blood vessel wall and within the blood vessel wall tissue;

FIG. 5 is a system view of exemplary implanted vital signs sensors incommunication with a watch and tablet computer;

FIG. 6 is a front perspective of an sensor mounting coupled to animplantable sensor housing and a sensor mounting retaining elementwrapped around a blood vessel and constructed in accordance with theprinciples of the present application;

FIG. 7 is a front perspective view of the sensor mounting platform shownin FIG. 6;

FIG. 8 is a front perspective view of a portion of the sensor mountingretaining element shown in FIG. 6;

FIG. 9 is a front cross-sectional view of the sensor mounting and thesensor mounting retaining element shown in FIG. 6 with the housing shownin FIG. 1 inserted within the sensor mounting;

FIG. 10 is a front perspective view of the housing shown in FIG. 9; and

FIG. 11 is a side view of the sensor mounting and the sensor mountingretaining element shown in FIG. 6.

DETAILED DESCRIPTION

As used herein, relational terms, such as “first” and “second,” “over”and “under,” “front” and “rear,” “in, within, and around” and the like,may be used solely to distinguish one entity or element from anotherentity or element without necessarily requiring or implying any physicalor logical relationship or order between such entities or elements.

Referring now to the drawings in which like reference designators referto like elements, there is shown in FIGS. 1-5 an exemplary implantablevital signs sensor device and monitoring system constructed inaccordance with the principles of the present application and designatedgenerally as “10.” As used herein the phrase “vital signs” refers tomeasurements related to a patient's, whether human or animal, basic bodyfunctions, including but not limited to, heart rate, blood pressure,blood pressure waveform, blood flow, respiratory rate, tidal volume,electrocardiogram, temperature, hemoglobin oxygen saturation, bodyposition, activity level, and related measurements. The device 10 mayinclude a housing 12 sized to be at least substantially retainedentirely within a blood vessel wall of a patient, and in particular, thewall of a vein or an artery.

The long-term implantable vital sign monitoring device 10 may monitorone or more of the following physiologic parameters in real-time todetermine a significant change from an individual patient's baselinepattern when living in the real-world environment: heart rate, heartrhythm, stroke volume, blood pressure, systemic vascular resistance,blood flow, myocardial contractility, valve function, cardiac timingintervals, respiratory rate, respiratory rhythm, tidal volume,hemoglobin oxygen saturation, heart sounds, lung sounds, upper airwaysounds, bowel sounds, temperature, electrocardiogram (lead 2, V2, andV5), activity level, body position, and location on the earth. Thelong-term implantable vital sign monitoring device 10 may also recordand store in memory one or more of the parameters for subsequentinterpretation.

For example, the housing 12 may be sized to span the wall thickness ofat least one of the internal thoracic (mammary) artery lateral thoracicartery, subscapular artery, intercostal artery, superior epigastricartery, carotid artery, aorta, renal artery, iliac artery, femoralartery, brachial artery, ulnar artery, and radial artery, which mayrange in wall thickness between approximately 100-1500 microns. Forexample, the housing 12 may be sized to span the wall thickness of atleast one of the internal thoracic vein, lateral thoracic vein, internaljugular vein, external jugular vein, renal vein, vena cava, axillaryvein, brachial vein, iliac vein, femoral vein and a peripheral vein,which may range in wall thickness between approximately 40-1000 microns.In addition, the housing 12 may be sized to span the wall thickness of apulmonary artery or a pulmonary vein, which may range in wall thicknessbetween approximately 40-1000 microns. The housing 12 may be composed ofbiodegradable and biocompatible materials such as polymers, biopolymers,hydrogels, collagen, elastin, hyaluronic acid and polylactic acid, suchthat it may degrade after a predetermined amount of time within thebody. Alternatively, the housing 12 may be composed of a biocompatiblematerial such as stainless steel, titanium, composite, ceramic,silicone, PTFE, PE, PVC, epoxy, or glass that does not degrade overtime. The housing 12 may be smooth or textured and coated with one ormore compounds that promote the adhesion and health of the vessel walltissue.

The housing 12 may include a first portion 14 sized to substantiallyspan the entirety of wall thickness of the artery or vein into which thehousing 12 is implanted. The first portion 14 may be substantiallycylindrical in shape and define a lumen 16 there through. For example,when inserted within the internal mammary (thoracic) artery, the firstportion 14 may define a length of approximately between 200-1,500microns and a surface area of approximately 1 mm². In otherconfigurations, the first portion 14 may define any hollow structuresized to substantially span the arterial wall thickness and provide thelumen 16 there through. The first portion 14 may further define a smoothouter surface to facilitate placement within the artery wall tissue, oralternately, may be threaded on its outer surface such that the firstportion 14 may be secured within the artery wall tissue through rotationof the first portion 14. The first portion 14 may be adhered within thearterial wall with an adhesive, or alternatively, may include a texturedsurface that promotes the adhesion, ingrowth, or attachment of thesurrounding vessel wall tissue or barbs or tines that engage thesurrounding tissue. The first portion 14 further includes an open firstend 18 configured to be positioned immediately adjacent to the basementmembrane and endothelial cells of the artery (tunica intima) such thatthe first open end 18 is not in contact with blood flowing within theartery or vein and a second open end 20 opposite the first end 18. In anexemplary configuration, the distance between the first open end 18 andthe blood stream when the first portion 14 is implanted within thearterial wall may be approximately 5 to 200 microns. In anotherconfiguration, the first open end 18 is substantially co-planar with thebasement membrane and endothelial cells. In another configuration, thefirst end can extend 5 to 200 micrometers into the artery lumen, incontact with the flowing blood. In another configuration, the first end18 may extend into the artery lumen, in contact with flowing blood.

Attached to the second end 20 may be a second portion 22 of the housing12. The second portion 22 may be positioned substantially orthogonal tothe first portion 14 and may extend across and contour at least aportion of the outer diameter of the arterial wall. For example, thesecond portion 22 may be substantially flat, rectangular, or round inshape, or alternatively, may define a curvature substantiallycorresponding to the curvature of the outer diameter of the arterialwall such that when the first portion 14 is received within the arterialwall, the second portion 22 may be pressed against the outer diameter ofthe arterial wall. The second portion 22 may further define a flatinterior surface and a rounded or bulbous exterior surface such that thesecond portion 22 protrudes a distance away from the outer diameter ofthe artery. The distance between the first end 18 and interior surfaceof the second portion 22 may be prefabricated such that when the secondportion 22 is pressed against the arterial wall, the first end 18 isposition immediately adjacent to the basement membrane and endothelialcells. Thus, the second portion 22 is configured to operate as a stopperto facilitate the insertion of the first portion 14 to the desired depthwithin the arterial wall.

Ultrasound may be used to measure the artery wall outer diameter, wallthickness, and inner diameter to determine the appropriate length/sizeof the housing 12, the first portion 14, and the second portion 22. Inparticular, the surgeon may select from pre-fabricated bases with aparticular height of the first portion 14 and length of the secondportion 22 to accommodate differently sized arteries or veins ordifferent wall thicknesses within the same patient or between differentpatients.

A vital signs sensor module 24 may be releasably or permanently insertedand received within at least a portion of the housing 12. For example,at least a portion of the vital signs sensor module 24 may be insertedthrough the second open end 20 into the lumen 16 of the housing 12. Themodule 24 may include a sensor housing 26 that includes one or morebiosensors, such as a force or pressure transducer, configured tomeasure one or more physiological parameters of the patient, which canbe transduced and correlated into one or more vital sign measurements.In particular, the sensor module 24 may include a pressure transducerconfigured to correlate a measured deflection of a diaphragm to a bloodpressure waveform and a blood pressure measurement, as discussed in moredetail below. The module 24 may be slideably received within the lumen16 such that it is retained within the lumen 16 and within the arterialwall. In one configuration, the module 24 includes a capillary tube 28with an optical fiber 30 or optical sensing mechanism 30, with atransducer diaphragm 32 on its distal tip. For example, the capillarytube 28 may have an optical fiber or optical sensing mechanism 30disposed within the tube 28 having a rigid, semi-flexible, or flexiblediaphragm 32 at its distal end, a portion of which is received withinthe lumen 16 and positioned to about the tunica intima cells of theartery proximate the first open end 18.

As shown in FIG. 1-2, the optical fiber 30 extends through the housing26 and extends outward from the artery in a position substantiallyperpendicular to the length of the artery, but may extend in anydirection. In one embodiment, the optical fiber 30 is not required andan optical sensing mechanism may be included as part of the module 24 tomeasure the displacement of the diaphragm 32 with each pulse to measurethe blood pressure (BP) waveform. Each pulse through the artery or veinmay cause the tissue and diaphragm 32 to move inward/outward a distanceproportional to the energy of the pulse wave, which may be correlated toproduce a measurement of the BP waveform. In one embodiment, thewaveform may be calibrated to produce an absolute blood pressuremeasurement using an external reference blood pressure sensor and anexternal atmospheric-barometric reference pressure sensor. In anexemplary configuration, the diaphragm 32 may be covered only by theendothelial cells, basement membrane, and/or a small amount ofconnective tissue. In one configuration the optics and electronics maybe housed within the sensor housing 26 and the capillary tube 28 and thediaphragm 32 may be housed within lumen 16. Once implanted in the body,the basement membrane and endothelial cells may grow from the edges ofthe injured artery wall tissue, over the surface of the diaphragm 32 toproduce a continuous biocompatible/hemocompatible interface. The outersurface of the flexible diaphragm 32 and distal portion of the housing12 may be textured or coated with compounds that promote healing of theartery wall tissue and the adhesion of the basement membrane andendothelial cell tissue. The very thin layer of cells and/or connectivetissue that may cover the outer surface of the diaphragm 32 maystabilize, and not affect, the measurement of the intravascular bloodpressure waveform. An external blood pressure reference sensor may beused to compensate for changes in the motion of the diaphragm 32 due tochange in the diaphragm 32 material and changes in the layer of cellsand connective tissue that may cover the diaphragm 32. Calibrations ofthe external blood pressure reference sensor may be performed inintervals or as needed to produce an accurate blood pressuremeasurement.

Examples of pressure transducers that may be included in the sensormodule 24 include those with single or multiple deflectable diaphragms32 with a Wheatstone bridge configuration, a single or multiplepiezoelectric crystal configuration, or an optical configuration thataccurately measures diaphragm 32 motion. Because the diaphragm 32 ispositioned adjacent to the layer of tunica intima, the module 24 mayproduce an accurate measurement of the intravascular blood pressurewaveform without distortion and without compressing or flattening of theartery wall, the artery lumen, the vein wall, or the vein lumen.

After implantation, the outer surface of the diaphragm 32 may remainclean or become coated with protein, carbohydrate, lipid and othercompounds. The outer surface of the diaphragm 32 can also become coatedwith basement membrane, other connective tissue and endothelial cells.The surface of the diaphragm 32 may be textured or coated with a naturalor synthetic biomaterial to enhance the adhesion of basement membraneand endothelial cells (tunica intima). Coating the outer surface of thediaphragm 32 with connective tissue or cells may change the physicalcharacteristics of diaphragm 32 motion. This coating layer (not shown)may become stable within days to weeks of implantation in the body. Thediaphragm 32 may also have a coating that inhibits the adhesion orattachment of proteins, connective tissue, endothelial cells, platelets,or coagulation factors. The diaphragm 32 may also have a coating ofgraphene, metal, glass, plastic, or ceramic. Thus, the implantedpressure/force sensor remains stable over time and may requireinfrequent re-calibration using an external BP cuff measurement systemas a reference. The reference BP cuff may also contain a barometer andthermometer (measures atmospheric pressure and temperature) to enhancecalibration of the implanted BP sensor.

In other configurations, the transducer's diaphragm 32 may be positionedexterior to the arterial wall, any depth within the arterial wall, orwithin the artery lumen exposed to flowing blood. For example, a post(not shown) may be located within the flowing blood (artery lumen) witha diaphragm 32 on its distal end or on the side of the post. Theintravascular post may be inserted at a right angle to the inner wall ofthe artery (90 degrees) or any angle relative to the inner wall of theartery (+320 to 0 to −320 degrees). The module's 24 diaphragm 32 may bepositioned on the side of the post toward the flow of blood and anyposition relative to the flow of blood, (0 to 360 degrees). Theintravascular post BP sensor module 24 can also be re-calibrated using areference upper arm BP cuff. An external barometer and thermometer maybe used to measure changes in atmospheric pressure and temperature toenhance calibration accuracy of the implanted BP sensor's output signal.In one embodiment, the thermometer may be disposed inside the sensorhousing 12 and may monitor a patient's core temperature and theperformance of the optical sensor.

The module 24 may further be configured to measure a patient's bloodpressure waveform in real-time. The waveform may be analyzed todetermine: heart rate, heart rate variability, stroke volume, strokevolume variability, myocardial contractility, vascular resistance,systolic and diastolic timing interval, aortic and mitral valvefunction, blood flow, and respiratory rate/pattern of ventilation. Forexample, the sensor modules 24 may include a processor configured tocorrelate the measured physiological parameters into a vital signsmeasurement that can be transmitted and/or stored with a memory. Themodule 24 may further include one or more additional vital signs sensorsdisposed within the housing 26 or disposed along or within otherportions of the module 24. For example, a hemoglobin oxygen saturationsensor, temperature sensor, an ECG electrode, an acoustic sensor such asa microphone, and an activity sensor may be included as part of themodule 24, as discussed in more detail below.

The module 24 may include a sensor module retaining element 34 disposedaround the circumference of the artery or vein. The sensor moduleretaining element 34 may be made from an elastic material that maysecure the sensor housing 12 and the module 24 within the artery walltissue while allowing the artery to expand and contract with each pulse.The sensor module retaining element 34 may include a plurality of links36, each link 36 being movably connected to an adjacent link 36 todefine a partial perimeter around the artery or vein. The plurality oflinks 36 may connect to the sensor housing 26 or the second portion 22to completely surround the artery or vein. The movability of the links36 allows for the artery to pulse as blood flows through it withoutconstricting the artery or vein and maintaining contact of the housing26 with the arterial or venous wall. The mechanism holding the links toeach other the sensor module and the blood vessel wall may have a small,moderate, or large degree of elasticity. The inner surface of each link36 may further define a porous/textured surface such that it may fusewith the arterial or venous wall tissue such that the arterial or venouswall and the links 36 may move substantially simultaneously duringpulsatile blood flow. The links may also have one or more through andthrough openings or channels that permit the ingrowth of vessel walltissue and vasa vasorum. A hemoglobin oxygen saturation sensor (pulseoximeter—SpO₂) 38 may be integrated within the body of one or more linksor the housing 26. For example, in a configuration with five links 36disposed around the circumference of the artery, a component of the SpO₂sensors 38 may be affixed within one or more links 36 to provide for aplurality of photoplethysmograph waveforms and SpO₂ measurements. In oneconfiguration, each link 36 has a recess (not shown) sized to receiveone of the SpO₂ sensor components, for example, the light source and/ordetector such that the only barrier between the blood flow within theartery and the SpO₂ sensor 38 is the arterial wall tissue. The pulseoximeter light source and light detector may be located on the same linkor separate links located on opposite sides of the artery. Each SpO₂sensor 38 may be in communication with the processor inside the housing28, for example, by a conductor disposed within the sensor moduleretaining element 34 connecting each SpO₂ sensor to each other and tothe processor. Optionally, other sensors, for example, an ECG sensor orother electrodes may be disposed within or around the sensor moduleretaining element 34. For example, electrodes may be disposed onopposite sides of the sensor module retaining element 34 to measure theelectrocardiogram, volume of blood flow, rate of blood flow,temperature, heart/lung/upper airway/gastrointestinal sounds,respiratory rate, and pattern of ventilation.

Now referring to FIG. 4, in other configurations, the sensor housing 26may be secured to the outside wall of the artery with a flexible andelastic stent, fabric, or mesh 40 disposed within a portion of the links36. These materials may have an open structure to decrease mass andfacilitate the ingrowth of tunica adventicia and vasa vasorum. Forexample, the sensor housing 26 may be fabricated with a flexible stent40 sized to be disposed around the circumference of the artery to affixthe capillary tube 28 and transducer diaphragm 32 within the lumen 16.The stent, fabric, or mesh 40 may be non-biodegradable such that it maynot degrade overtime, or alternatively, may be biodegradable such thatover a predetermined amount of time the stent, fabric, or mesh 40 maydegrade leaving the module 24 affixed to the tunica adventicia tissueand the capillary tube 28 affixed to the artery wall tissue. The stent,fabric, or mesh may define a larger diameter to that of the module 24 tosurround the module 24 and stents 40. The stent, fabric, or mesh may bemade out of natural or synthetic materials that are elastic andflexible, including polymers and biopolymers such as silicone, ePTFE,Dacron®, polyurethane, polypropylene, PHEMA, polylaetate, PLG, collagen,elastic, hyaluronic acid, composites, graphene/carbon nano-tubes, metalsand ceramics. Surgical clips, sutures, or a tissue adhesive are furthercontemplated to be used to secure the module 24 to the artery walltissue in combination with the stent 40 or as an alternative. Forexample, as shown in FIG. 3B, sutures are thread through a portion ofeach link 36 and attach directly to the module 24. Each link 36 maydefine one or more apertures or channels through with the sutures,belts, or stents 40 may be disposed to facilitate securing the housing26 to the arterial wall.

Referring now to FIG. 5 which illustrates the location of sensor module24 implanted around the right internal mammary artery and an additionalsensor module 42 a implanted within the subcutaneous tissue of the rightupper chest wall, and a second additional sensor module 42 b implantedwithin the subcutaneous tissue of the left upper chest wall. Each sensormodule 24, 42 a, and 42 b, can be constructed with one or multiple vitalsign sensors per module. For example, subcutaneous tissue sensor modules42 a and 42 b may include an EKG electrode, a microphone, a GPS sensor,an accelerometer, and a temperature sensor. The implanted blood pressuresensor 26 may be connected to one or more subcutaneous tissue sensormodules 42 a and 42 b using a biocompatible lead. One or more of thesubcutaneous tissue sensor modules 42 a and 42 b may have a battery,microprocessor, digital memory, diagnostic/therapeutic controlalgorithms and telemetry to an external display, data analyzer and datarecorder. The implanted sensors 24, 42 a, and 42 b may communicate withan external controller 44 with a display through radiofrequencytelemetry. For example, the controller may be a Smartphone, tabletdevice, or smart watch, such as an iPhone®, iPad®, Apple Watch® 44 (FIG.5), or FitBit® or another device that receives information, with anapplication in communication with a processor having processing circuityconfigured to communicate with the implanted sensors 24, 42 a, and 42 band record and display the measured information. In another example, theSmartphone, tablet device, smart watch or another device may receiveinformation, analyze the vital sign trend data, produce alerts andalarms, and communicate with a patient, care-giver or other medialprofessional. In one configuration, the user may wear a smart watch withbuilt-in wireless communication to communicate with the implantedsensors 24, 42 a, and 42 b, correlate the measured data, and display theresults. The controller 44 may be used by the patient and physician todisplay and processes the real-time and recorded sensor data, calibratethe sensors, and troubleshoot the sensors. The controller 44 may containa barometer that measures the real-time atmospheric barometric pressureto produce a calibrated and accurate absolute blood pressuremeasurement. The controller 44 may contain a thermometer that measuresthe real-time atmospheric temperature to produce a calibrated andaccurate absolute blood pressure measurement.

The implanted sensors 24, 42 a, and 42 b may be in communication with acharge storing device (battery) 46 implanted within the body separatefrom the sensors 24, 42 a, and 42 b or within the sensor module 24, 42a, or 42 b. The charge storing device 46 may be a hermetically sealedbattery implanted within the body in wired communication with theimplanted sensors 24, 42 a, and 42 b. The implantable battery 46 may bere-charged across the skin using an external power source by, forexample, inductive charging. In an alternate embodiment, the energy forthe implanted sensors 24, 42 a, and 42 b to function may be transmittedfrom the outside of the body through the skin and the subcutaneoustissue using electromagnetic coupling or light coupling. Transmission ofexternal power to the internal sensors 24, 42 a, and 42 b requires lowenergy and thus a short transmission distance. The external power sourcemay be located near or adhered to the skin surface for extended periodsof time to power the implanted vital sign monitoring device or rechargethe implanted battery. Internal sensors 24, 42 a, and 42 b maycommunicate through radio frequently telemetry and may have an internalpower supply or an external power supply.

The module 24 containing the blood pressure sensor may be implantedaround the internal thoracic (mammary) artery (between the3^(rd)-4^(th), 4^(th)-5^(th) 5^(th)-6^(th) intercostal space) usinglocal or general anesthesia. That artery is located perpendicular to theribs, approximately 1 cm lateral to the sternum, and between the innerand middle intercostal muscles. In an exemplary configuration, themodule 24 may be implanted at the level of the aortic valve to minimizethe effects of body position on the arterial pressure waveform and theabsolute blood pressure measurement. In an exemplary method ofimplantation, the surgeon may use a small needle, punch or an automatedstapling device to puncture the wall of the artery or vein. In partbecause the needle may create a tapered opening in the arterial wall,the first portion 14 of the housing 12 may be inserted within theaperture created by the needle such that the first open end 18 issubstantially planar or partially recessed from the basement membraneand endothelial cells. In other configurations, the needle may pierceentirely through the wall of the blood vessel. The lumen 16 of thehousing 12 may be slid around the circumference of the needle andaffixed inside the aperture with the artery wall tissue. The capillarytube 28 of the module 24 may then be inserted within the lumen 16 of thehousing 12 for affixation within the housing 12 such that one or moretransducer diaphragms 32 may be positioned substantially coplanar withthe opening of the first end 18. The elastic element 34 and stents 40may be positioned around the outside of the artery or vein and attachedto the sides of the module 24 to secure the housing 12 within the arterywall tissue and the module 24 to the outside of the blood vessel wall.

In an exemplary configuration of the module 24, as shown in FIG. 3, twoor more blood pressure sensor waveform transducers can be positionedaround the artery with the transducer's diaphragm 32 immediatelyadjacent to the endothelial cells. The SpO₂ sensor 38 may be configuredwith one or more light sources and light detectors external to theartery wall (tunica adventicia); opposite one another (12 o'clock and 6o'clock positions). This alignment may produce a real-timephotoplethysmography signal with a high signal-to-noise ratio andminimal motion artifact. The SpO₂ sensor's 38 light sources anddetectors may also be located within the artery wall tissue adjacent tothe endothelial cells. The external surface of the module 24 (containingthe BP sensor and SpO₂ sensor), the stents 40, and the additional sensormodules 42 a and 42 b may have a metal conducting surface, for example,an electrode that can measure the real-time electrocardiogram signal ofthe heart (ECG or EKG) and electrical signals due to movement of thediaphragm and chest wall. The module 24 and additional sensor modules 42a and 42 b may also contain a temperature thermistor that continuouslymeasures the core or blood temperature and one or more microphones thatmonitor and record the heart sounds (phonocardiogram), lung sounds,upper airway sounds, and gastrointestinal sounds.

The measured vital signs from module 24 and/or implanted sensors 42 aand 42 b may be used to alert, diagnose, and/or treat associateddiseases or conditions that can be correlated from the measured vitalsigns. For example, measurements taken from one or more of the implantedsensors, namely, ECG, blood pressure waveform, pulse oximeter,thermometer, microphone, accelerometer, GPS may be combined andprocessed in real-time to provide diagnostic and/or therapeuticrecommendations and/or therapies to the patient. Trend data from theimplanted sensors can be combined with trend data from one or morenon-invasive sensors, for example, a scale measuring body weight, levelof activity, body position, sleep patterns, and a camera capturing animage of a patient's head, neck, and torso, and sensors which measureblood pressure and hemoglobin saturation, to provide diagnostic and/ortherapeutic recommendations and/or therapies to the patient.

In an exemplary configuration, the one or more measured vital signs maybe monitored in an ambulatory patient and displayed and/or stored on thecontroller 44 or a remote database, for example, to a physician's officeand/or a central monitoring station with real-time diagnostic algorithmsand a detailed patient electronic medical record (EMR). The measuredvital signs may then be compared against a threshold value predeterminedby the patient's physician or an algorithm based on the patient'sbaseline vital sign information. For example, based on the user'sweight, height, age, family history, medications, medical history, andprior vital signs data, the algorithm may determine a threshold value orrange for one or more of the vital sign measurements that the processorin the controller 44 or a remote location, may compare against eachother to determine if a medical condition exists and alert the patient,for example, via a call, text, or alarm to the controller 44, athird-party Smartphone, the patient's Smartphone, or an email thatsummarizes the condition. The algorithm may trigger an event to recordimportant vital sign sensor data and transmit the trend data to theexternal control module and central monitoring station for review andclinical analysis. Ambulatory patients may receive audible or visualalerts and alarms when the vital sign sensor algorithms detect asignificant change in vital sign trend data. The patient may manuallyenter a diary of symptoms, signs, meals and medications into thediagnostic/therapeutic software algorithms to manage their disease withgreater safety and efficacy. Clinicians at a central monitoring systemcan communicate with the patient via cell phone to initiate/adjustmedical therapy and summarize the effects of that therapy over time.Described below are several diagnostic algorithms that may usemulti-modal monitoring (trend data from more than one vital sign sensor)to diagnose the following conditions:

Myocardial Ischemia and Myocardial Infarction—

real-time monitoring of the ECG can be used to diagnose myocardialinfarction and ischemia by analyzing ST segment depression (horizontalor down-sloping) or elevation in relation to heart rate, BP, & activitylevel; new onset Q waves; unifocal and multifocal premature ventricularcontractions, ventricular tachycardia, ventricular fibrillation;premature atrial contractions; supraventricular tachycardia, atrialfibrillation, new conduction delays, and new heart block related tomyocardial ischemia, myocardial infarction and heart failure. Real-timemonitoring of the blood pressure waveform can detect changes in BP,heart rate, stroke volume, myocardial contractility, systemic vascularresistance, cardiac output, systolic/diastolic timing intervals, valvefunction, and respiratory rate that typically occur with myocardialischemia at rest and with exercise. Real-time monitoring of cardiacsounds can detect wheezing, rhales, S-3 sound, and a new murmur ofmitral/aortic valve regurgitation due to myocardial ischemia, LVdysfunction, and pulmonary edema. Real-time monitoring with a pulseoximeter may detect an acute decrease in the arterial hemoglobin oxygensaturation that may occur with myocardial ischemia at rest and withexercise. Changing from a stable to an unstable pattern would beconsidered a medical emergency requiring increased vigilance andoptimized/timely medical therapy.

Congestive Heart Failure and Pulmonary Edema—

Real-time monitoring of the blood pressure waveform may be used todetect changes in myocardial contractility, stroke volume, stroke volumevariability, heart rate, heart rate variability, systolic/diastolictiming intervals, valve function and respiratory rate that may occurwith myocardial ischemia, infarction, cardiomyopathy and heart failure.Real-time monitoring of cardiac & lung sounds can detect wheezing,rhales, S-3 sound, and a new murmurs due to LV dysfunction and acutepulmonary edema. Real-time monitoring with a pulse oximeter may detectan acute decrease in the arterial hemoglobin oxygen saturation. Changingfrom a stable to an unstable pattern would be considered a medicalemergency requiring increased vigilance and optimized/timely medicaltherapy.

Hypertension (Mild, Moderate & Severe)

real-time monitoring of the blood pressure waveform pattern may be usedto diagnose hypertension (mean, systolic & diastolic BP>target range forage) and determine the effectiveness of medical/drug/device therapy. Forexample, a sustained upward trend for systolic, diastolic, and meanblood pressure and/or persistent tachycardia in relation to activity,rest, and sleep may require a change in medication or medial therapy.Medication dose may be adjusted to real-time BP data and trend data.Monitoring the ECG can detect the acute and chronic effects ofhypertension on left ventricle wall thickness and myocardial electricalactivity (LV hypertrophy with strain pattern). New onset moderate/severehypertension or changing to an unstable BP pattern would be considered amedical emergency requiring increased vigilance and optimized/timelymedical therapy.

Atrial Fibrillation or Supraventricular Tachycardia—

real-time monitoring of the ECG can diagnosis new onset or recurrentatrial fibrillation and/or supraventricular tachycardia that occursspontaneously or secondary to myocardial ischemia, CHF, or hypertension.Real-time monitoring of the arterial BP waveform can detect thehemodynamic significant of an arrhythmia (decreased BP, stroke volume,and cardiac output). Monitoring the pulse oximeter during the arrhythmiacan detect decreased hemoglobin oxygen saturation due to decreased andunstable blood flow. New onset atrial fibrillation, SVT or changing toan unstable rhythm pattern would be considered a medical emergencyrequiring increased vigilance and optimized/timely medical therapy.

Acute Bronchospasm (Asthma)—

Changes in the vital signs measurements may be used to diagnose upperairway obstruction, large airway obstruction, small airway obstruction,bronchospasm (due to asthma or bronchitis), and pneumothorax. Real-timemonitoring of cardiac, lung, and upper airway sounds can detectwheezing, rhales, rhonchi, increased respiratory rate/tidal volume(minute ventilation) and prolonged exhalation (increased work ofbreathing). Monitoring the arterial BP waveform can detect increasedheart rate, increased heart rate variability, decreased stroke volume,increased stroke volume variability, and decreased cardiac output.Monitoring the ECG can detect an increased HR, decreased HR variability,arrhythmias, and acute right ventricle strain. Monitoring the pulseoximeter can detect an acute decrease in hemoglobin oxygen saturation.New onset bronchospasm with a high work of breathing and decreasedhemoglobin oxygen saturation would be considered a medical emergencyrequiring increased vigilance and optimized/timely medical therapy.

Chronic Obstructive Pulmonary Disease & Respiratory Failure—

Changes in the vital signs measurements may be used to diagnose acuterespiratory failure and a worsening of chronic bronchitis and emphysemadue to acute bronchitis or pneumonia. For example, an increase inrespiratory rate and minute ventilation, coughing, wheezing, decreasedhemoglobin oxygen saturation, persistent tachycardia, myocardialischemia, right heart strain, and elevated temperature may be indicativeof such a condition. A persistently high work of breathing and decreasedhemoglobin oxygen saturation would be considered a medical emergencyrequiring increased vigilance and optimized/timely medical therapy.

Intestinal Diseases (Crohn's Disease, Ulcerative Colitis,Diverticulitis, Ischemia)—

Changes in the vital signs measurements may be used to diagnosedecompensation of inflammatory bowel disease. For example,increased/decreased bowel sounds (motility), elevated temperature,tachycardia, hypotension, decreased blood flow, tachypnea, decreasedhemoglobin oxygen saturation may all be indicated of such a condition.

Pulmonary Embolism—

Changes in the vital signs measurements may be used to diagnose apulmonary embolism. For example, acute onset wheezing, increasedrespiratory rate, increased minute ventilation, tachycardia,atrial/ventricular arrhythmias, right ventricle strain pattern on EKG,decreased hemoglobin oxygen saturation, elevated temperature, decreasedstroke volume, decreased cardiac output, and hypotension, may beindicated of such a condition. Any pulmonary embolism would beconsidered a medical emergency requiring increased vigilance andoptimized/timely medical therapy.

Hemorrhage or Dehydration—

Changes in the vital signs measurements may be used to diagnosesignificant dehydration due to bleeding, edema, decreased oral intake,excess urination, or diarrhea. For example, increase in heart rate,peripheral vascular resistance, respiratory rate, minute ventilation anda decrease in stroke volume, cardiac output, blood pressure, blood flow,and hemoglobin oxygen saturation, may be indicated of moderate to severeblood loss and/or dehydration.

The above conditions are merely exemplary of the number of ways thevital sign measurements determined from the sensor module 24 and/oradditional sensor modules 42 a and 42 b may be measured and correlatedin real-time against a patient established threshold to either signal analert to the user, signal an alert to a medical professional (primarycare physician or central monitoring station), or record the data oradditional data for further evaluation. For example, a patient withknown atrial fibrillation may have a different blood pressure thresholdvalue compared to the blood pressure of a patient without atrialfibrillation. As such, the threshold value can be programmed by thedoctor into the controller 44 or automatically by the remote database,such that when that threshold value is exceeded or falls below thatthreshold in a real-time ambulatory setting, depending on the thresholdvalue, an alert may be sent to the patient, the central monitoringstation, and/or the patient's physician. Similarly, patients with otherconditions may have different thresholds for each vital sign measurementmeasured by the module 24 and/or 42 and 42 b such that each module 24 incombination with the controller 44 may be personalized for each patientto provide an early warning sign of an individual condition prior to anadverse event. Alerts and alarms can be based upon a simple threshold, apredicted threshold, or based upon a model of the patient's physiology.Moreover, based on the vital signs measurements, a therapeutic algorithmmay also be used in combination with the diagnostic algorithm torecommend and/or implement therapies for the patient based on themeasured vital signs compared to the patient's individual thresholdvalues or ranges. For example, the therapeutic algorithm may operate inthe above conditions as follows:

Myocardial Ischemia—

Physicians and patients currently titrate medications in response tosymptoms such as “chest pain” (angina) despite the fact that greaterthan 80% of myocardial ischemia is silent and many “pains in the chest”are due to non-cardiac causes. Medications for ischemic heart diseasemay be dosed once or multiple times per day based upon quantitativevital sign data. Real-time data may be used to “recommend” an adjustmentin medical therapy (nitrates, ACE inhibitors, beta blockers, calciumchannel blockers, aspirin, anticoagulant, and oxygen) based on thepatient's medical history and historical vital signs measurements. It isfurther contemplated that the real-time vital sign sensor system andclosed-loop therapeutic algorithms may automatically deliveranti-ischemia medications using drug infusion pumps and/or oxygen usingan oxygen source and regulator. Real-time data may also be used toautomatically adjust electrical nerve tissue stimulation devices andcardiovascular blood pump devices that optimize blood pressure and bloodflow in a patient with a sick heart.

Congestive Heart Failure & Pulmonary Edema—

Changes in the patient's vital sign pattern may be used to detect theonset of CHF and pulmonary edema in the early stages as discussed above,such that management can occur in the ambulatory setting; avoiding avisit to the emergency room and admission to an intensive care unit.Real-time vital sign sensor data may be used to recommend an acutechange in medical therapy (diuretics, catecholamines, digitalis,nitrates, beta blockers, calcium channel blockers, ACE inhibitors, andoxygen). It is further contemplated that the real-time vital sign sensorsystem and closed-loop therapeutic algorithms may automatically delivermedications, oxygen, pacemaker therapy, ventricular assist devicetherapy, and total artificial heart therapy that may increase myocardialcontractility, control HR, control BP, control blood flow, oxygenconcentration, and decrease systemic vascular resistance using druginfusion pumps and electrical stimulation.

Hypertension—

Real-time analysis of the BP waveform may calculate heart rate, heartrhythm, stroke volume, arterial blood flow, myocardial contractility,and systemic vascular resistance. Vital sign sensor data may be used torecommend an acute change in medical therapy (diuretics, beta blockers,alpha blockers, vasodilators, ACE inhibitors, calcium channel blockers)and monitor the effectiveness of that medical therapy. It is furthercontemplated that the real-time vital sign sensor system and closed-looptherapeutic algorithms may automatically deliver anti-hypertensionmedications using drug infusion pumps and electrical therapy of nervoustissue to maintain the mean, systolic, and diastolic BP is the targetrange during rest, exercise, sleep, and illness.

Arrhythmia—

real-time vital sign sensor data may be used to recommend an acutechange in medical therapy (beta blockers, calcium channel blockers, andmembrane stabilizers). It is further contemplated that real-time vitalsign sensor system and closed-loop therapeutic algorithms mayautomatically deliver anti-arrhythmia medications using drug infusionpumps; and anti-arrhythmia electrical shock therapy using adefibrillation shock, a cardioversion shock and/or override pacemakershocks.

Asthma—

real-time vital sign sensor data may be used to recommend medicaltherapy (oxygen, catecholamine inhaler, steroid inhaler, parenteralcatecholamines) during an acute asthma attack. It is furthercontemplated that the real-time vital sign sensor system and closed-looptherapeutic algorithms may automatically deliver anti-inflammatory andbronchodilator medications using drug infusion pumps, oxygen using anoxygen source/regulator, and electrical stimulation of nervous tissue toreduce bronchospasm and inflammation.

Chronic Obstructive Pulmonary Disease (COPD)—

real-time vital sign sensor data may be used to recommend an acutechange in medical therapy (oxygen, catecholamine inhaler, steroidinhaler, parenteral catecholamines). It is further contemplated that thereal-time vital sign sensor system and closed-loop therapeuticalgorithms may automatically deliver anti-inflammatory andbronchodilator medications using drug infusion pumps, oxygen using anoxygen source/regulator, and electrical stimulation of nervous tissue toreduce bronchospasm and inflammation.

Chronic Intestinal Diseases—

real-time vital sign sensor data may be used to recommend an acutechange in medical therapy (intravenous fluids, oxygen,enteral/parenteral steroids, and enteral/parenteral anti-inflammatorymedications). It is further contemplated that the real-time vital signsensor system and closed-loop therapeutic algorithms may automaticallydeliver anti-inflammatory, pro-peristalsis, or anti-peristalsismedications using drug infusion pumps.

The measured vital signs data may further be processed to determinewhether trend vital sign data is “abnormal” or “extreme” relative to amodel of a universal healthy/stable patient or adapted to an individualpatient. For example, hundreds to thousands of hours of patient vitalsign data from any one or all of the sensors may be recorded andanalyzed. Large data sets may be split into (1) training sets, (2)control sets, and (3) test sets. Clinical experts may review the trenddata and label specific patterns as “crisis events” or “error codes.”The algorithms may learn from an individual patient's physiologicalpatterns and determine when the trend data is “abnormal” or “extreme”with high sensitivity and specificity (minimal false alerts/alarms andfew missed “real” events). The real-time method may estimate the extremevalue distributions of multivariate, multimodal mixture models foranalysis of complex datasets from an array of physiological vital signsensors.

Referring now to FIG. 6, in another configuration of the implantabledevice 10, the sensor module 24 and its sensor housing 26 may be coupledto a sensor mounting 48 configured to be positioned around a portion ofthe wall of a blood vessel. The sensor mounting 48 may be composed ofbiocompatible materials such as titanium, stainless steel, or plasticand is configured to at least partially contour the surface of the wallof the blood vessel. In one configuration, the sensor mounting 48 isconfigured to permanently retain the sensor module 24 and in otherconfigurations may be configured to releasably couple the sensor module24. The sensor mounting 48 may include a sensor mounting retainingelement 50, which may be same or similar to the sensor module retainingelement 34. The sensor mounting retaining element 50 is configured tosurround and wrap around the blood vessel and to releasably orpermanently couple with the sensor mounting 48. The sensor mountingretaining element 50 is configured to maintain the position of thesensor mounting 48 within respect to the blood vessel.

Referring now to FIGS. 6 and 7, the sensor mounting 48 may include aplatform 52 configured to receive the sensor housing 26. In exemplaryconfiguration, the platform 52 is elongate in shape and defines aninterior surface 54 and an exterior surface 56. The interior surface 54may be substantially planar such that when the sensor housing is mountedto the sensor mounting 48 it is substantially flush with the platform52. The exterior surface 56 may be curved along the entire length or aportion of the length of the platform 52 to match or substantially matchthe curvature of the blood vessel. For example, the exterior surface 56may be positioned to face the exterior of the wall of the blood vesseland define a concavity such that the platform 52 may curve around theblood vessel wall. In other configurations, the exterior surface 56 maybe substantially planar along its length.

Extending away from the platform 52 may be a pair of projecting arms 58a and 58 b (collectively referred to herein as projecting arms 58). Eachof the projecting arms 58 may include a proximal portion 60 extendingaway from the platform 52 in a direction substantially orthogonal to thesubstantially planar interior surface 54 and a distal portion 62extending inward and away from the proximal portion 60 in a directionsubstantially parallel to the substantially planar interior surface 54.Each of the proximal portion 60 may cooperate with the exterior surface56 of the platform 52 to define a curvature similar to the curvature ofthe blood vessel. The projecting arms 58 are configured to lock thehousing 26 within the sensor mounting 48. For example, as shown in FIG.6, the sensor housing 26 may include a base 64 configured to pressagainst the platform 52 when the sensor housing is inserted within theinterior of the sensor mounting 48. The base 64 may extend underneaththe distal portion 62 of each of the projecting arms 58 such that sensorhousing 26 is locked to the sensor mounting 48. Optionally, each of theprojecting arms 58 may define a slot 66 configured to receive a tab 67(shown in FIG. 10) on the base 64. When the base 64 is received withinthe sensor mounting 48, the tab 67 on opposite sides of the base 64 mayslide within the slot 66 to lock the sensor housing 26 to the sensormounting 48.

Continuing to refer to FIG. 7, the platform 52 may define an aperture 68proximate its midpoint or at any position along its length. The aperture68 is sized to receive and retain a portion of the sensor module 24. Forexample, the aperture 68 may be sized to receive the first portion 14 ofthe housing 12 such that when the first portion 14 of the housing 12 isinserted within the aperture 68, the first portion may extend a distanceaway from the platform 52 and into a portion of a blood vessel. Theaperture 68 may be sized to receive a predetermined sized housing 12based on the outer diameter wall thickness of the blood vessel to beinserted. For example, the aperture 68 may define a length substantiallythe same as the length of the first portion 14 for a particular artery.Thus, platforms 52 having differently sized apertures 68 may be selecteddepending on the thickness of the blood vessel wall in which the sensormodule 24 is inserted. To provide for proper depth of insertion withinthe platform 52 and therefore the blood vessel, the platform 52 mayfurther define an annular recess 70 disposed about the aperture 68. Forexample, the recesses 70 may be step-down in height from the platform 52and the aperture 68 may be a step-down in height from the recess 70. Forexample, as shown in FIG. 9, the second portion 22 of the housing 12 issized to be received within the recess 70 and when the second portion 22of the housing 12 is received within the recess 70, the second portion22 and the platform 52 are substantially co-planar. Thus, the recess 70functions to limit the distance the first portion 14 of the housing 12may be advanced through the aperture 68 to provide for proper alignmentof the diaphragm 32. A surgeon may use non-invasive ultrasound todetermine the outer diameter, inner diameter, and thickness of bloodvessel wall to determine the optimal combination of platform aperture 68height, first portion 14 length, and second portion 22 length to locatethe diaphragm 32 adjacent to the endothelial cells and theircorresponding basement membrane. The underneath side of the secondportion 22 may be secured to the superior surface of the platform's 52annular recess 70 using adhesive or double sided-tape

Referring now to FIGS. 6-8, the sensor mounting retaining element 50 mayinclude the plurality of connected and spaced apart links 36 asdescribed above, or alternatively may be a single sheet, for example afabric, elastic band, or an adhesive. In either configuration, thesensor mounting retraining element 50 is configured to wrap around thewall of the blood vessel. In the configuration in which the sensormounting retaining element 50 includes the plurality of spaced apartlinks 36, the links 36 may include some or all of the features andcomponents described above, including but not limited to the SpO₂sensors. The links 36 may be composed implantable grade titanium,stainless steel, plastic, or another implantable grade material, oralternatively, may be composed of a biodegradable or bioabsorbablematerial. In one configuration, each link 36 of the plurality of links26 may be over molded with silicone. The silicone over mold may definemesh like pattern to promote tissue growth further provide optimalmounting strength while minimizing compression for the specific bloodvessel. In one configuration, the links 36 may be evenly spaced toevenly distribute the force around the blood vessel. The number of links36 may be increased or decreased for different blood vessels.

In one configuration, the links 36 may be connected by one or morestrips 72 that extend through or on each of the links 36. In theconfiguration shown in FIG. 6, two strips 72 are shown extending througheach of the links 36. The strips 72 may be composed of silicon or otherelastic materials, such as TPU, TPE, and the like such that they areflexible with the movement of the blood vessel. In particular, theelasticity of the strips 72 provide for flexibility of the sensormounting retaining element 34 such that when the blood vessel pulsesowing to systolic and diastolic pressure within the artery, the sensormounting 48 maintains its positions with respect to the artery as theplurality of links 36 and the strips 72 flex to distribute the forcefrom the pulsating blood vessel to the plurality of links 36 and thestrips 72. The plurality of links 36 may include a first end link 74 anda second end link 76 at the ends of the sensor mounting retainingelements 48. The first end link 74 is configured to couple to a firstside of the sensor mounting 48 and the second end link is configured tocouple to a second side of the sensor mounting 48. In one configuration,as shown in FIG. 7, the sensor mounting 48 defines a first channel 78 onthe first side of the sensor mounting 48 and a second channel 80 on thesecond side of the sensor mounting 48. The first end link 74 isconfigured to lock within the first channel 78 and the second end link76 is configured to lock within the second channel 80. For example, theend links 74 and 76 may be configured as v-slots to slide in and lock into the mounting platform 48. In other configurations, the end links 74and 76 may be coupled to the sensor mounting 48 by being molded to thesensor mounting 48 to form a unitary component. In one configuration, atleast one of the end links 74 and 76 are permanently coupled within itscorresponding channels 78 and 80 and the other end 74 or 76 isreleasably couplable to its corresponding channel 78 and 80.

Referring now to FIG. 9, the housing 12 may be coupled or otherwiseengaged to a portion of the sensor housing 26 such that the sensorhousing 26 rests on the housing 12. For example, as discussed above, aportion of the sensor module 24 may extend into and through the housing12 and into the blood vessel to position the diaphragm 32 adjacent tothe endothelial cells and basement membrane. A thin layer of endothelialcells, basement membrane, and connective tissue may grow over thesurface of the diaphragm 32 within, for example, 24 hours to produce ahemo-compatible surface that minimizes platelet adhesion and thrombusformation. For example, as shown in FIG. 10, the second portion 22 ofthe housing 12 may define a diameter larger than the diameter of thefirst portion 14 with the lumen extending there through. Although thefirst portion 14 is shown as cylindrical and the second portion 22 isshown as annular, any shape is contemplated. In on configuration, whenthe housing 12 is inserted within the aperture 68 and the second portion22 is nested within the recess 60, the second portion 22 may extend adistance within the blood vessel through the aperture created by apuncture in the blood vessel wall. In one configuration, the secondportion 22 may extend a predetermined distance into the wall of theblood vessel between, for example, 1-1500 microns and be embedded withinthe wall of the blood vessel such that the diaphragm 32 is within theblood vessel wall adjacent to the endothelial cells and basementmembrane. In other configurations, for example, as shown in FIG. 11, thecapillary tube 28 and/or fiber optics 30 may extend through the housing12 and the blood vessel wall such that the diaphragm 32 is positionedadjacent to the endothelial cells and basement membrane. In otherconfigurations, the distal end of the first portion 14 and the sensordiaphragm 32 are positioned within the vessel wall tissue some distanceproximal to the endothelial cells and basement membrane. In otherconfigurations, the distal end of the housing first portion 14 and thesensor diaphragm 32 are positioned in the vessel lumen in direct contactwith the blood stream. In other configurations, no housing 12 isincluded, or the housing 12 degrades over time, and the sensor module 24fits within the sensor mounting 48 and the capillary tube 28 and/orfiber optics 30 extend through the recess 68 and into the lumen of theblood vessel.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. An implantable device for a patient having ablood vessel with a blood vessel wall, comprising: a sensor mounting,the sensor mounting being sized and configured to at least partiallycontour the wall of the blood vessel and to receive and retain a sensormodule; and a sensor mounting retaining element coupled to the sensormounting, the sensor mounting retaining element being configured to wraparound the blood vessel.
 2. The device of claim 1, wherein the sensormounting includes an elongate platform defining a substantially planarsurface.
 3. The device of claim 2, wherein the elongate platform definesan aperture sized to receive a portion of the sensor module.
 4. Thedevice of claim 3, further comprising a housing sized to be receivedwithin the aperture, the housing being sized and configured to receive aportion of the sensor module.
 5. The device of claim 4, wherein thehousing includes a first portion defining a first open end, a secondportion opposite the first end, and a lumen there through, the firstportion being sized to be at least partially implanted within the wallof the blood vessel.
 6. The device of claim 5, wherein the platformdefines a recess around the aperture, and wherein the second portion ofthe housing is sized to be received within the recess and when thesecond portion of the housing is received within the recess, the secondportion and the platform are substantially co-planar.
 7. The device ofclaim 1, wherein the sensor mounting retaining element includesplurality of connected and spaced apart links.
 8. The device of claim 7,wherein the plurality of connected and spaced apart links include atleast on elastic strip connected through each of the plurality ofconnected and spaced apart links and configured to connect the pluralityof links together.
 9. The device of claim 7, wherein the plurality ofconnected and spaced apart links are bioabsorbable.
 10. The device ofclaim 7, wherein the plurality of connected and spaced apart linksincludes a first end link and a second end link, and wherein the sensormounting includes a first side and a second side opposite the firstside, and wherein the first end link is configured to couple to thefirst side of the sensor mounting and the second end link is configuredto couple to the second side of the sensor mounting.
 11. The device ofclaim 10, wherein the sensor mounting includes a first channel on thefirst side of the sensor mounting and a second channel on the secondside of the sensor mounting, and wherein the first end link isconfigured to lock within the first channel and the second end link isconfigured to lock within the second channel.
 12. An implantable devicefor a patient having a blood vessel with a blood vessel wall,comprising: a sensor mounting, the sensor mounting being sized andconfigured to at least partially contour the wall of the blood vessel; asensor module, the sensor mounting being configured to receive andretain the sensor module and to measure at least one patient vital sign;and plurality of connected and spaced apart links coupled to the sensormounting, the plurality of connected and spaced apart links beingconfigured to wrap around the blood vessel and to maintain the positionof the sensor module with respect to the blood vessel during pulsatilemovements of the blood vessel.
 13. The device of claim 12, wherein thesensor mounting includes an elongate platform defining a substantiallyplanar surface and a pair of projecting arms extending away from thesubstantially planar surface in a direction substantially orthogonal tothe planar surface.
 14. The device of claim 13, wherein each of the pairof projecting arms includes a proximal portion and a distal portion, andwherein the proximal portion of each of the pair of projecting armsdefines a curvature configured to contour the wall of the blood vessel,and wherein the distal portion of each of the pair of projecting armsextends inward.
 15. The device of claim 14, wherein the sensor moduleincludes a base, and wherein a portion of the base extends underneaththe distal portion of each of the pair of projecting arms to lock thesensor module to the sensor mounting.
 16. The device of claim 13,wherein the platform defines an aperture, and wherein at least a portionof the sensor module is received within the aperture.
 17. The device ofclaim 16, further comprising a housing sized to be received within theaperture, the housing being sized and configured to receive a portion ofthe sensor module.
 18. The device of claim 17, wherein the housingincludes a first portion defining a first open end, a second portionopposite the first end, and a lumen there through, the first portionbeing sized to be at least partially implanted within the wall of theblood vessel.
 19. The device of claim 18, wherein the platform defines arecess around the aperture, and wherein the second portion of thehousing is sized to be received within the recess and when the secondportion of the housing is received within the recess, the second portionand the platform are substantially co-planar.
 20. An implantable devicefor a patient having a blood vessel with a blood vessel wall,comprising: a sensor mounting, the sensor mounting being sized andconfigured to at least partially contour the wall of the blood vessel,the sensor mounting including an elongate platform defining asubstantially planar surface and a pair of projecting arms extendingaway from the substantially planar surface in a direction substantiallyorthogonal to the planar surface, the elongate platform defining anaperture; a sensor module, the sensor mounting being configured toreceive and retain the sensor module and to measure a blood pressurewaveform, the sensor module including a base, and wherein a portion ofthe base extends underneath the distal portion of each of the pair ofprojecting arms to lock the sensor module to the sensor mounting; ahousing, the housing being sized to be received within the aperture, thehousing being sized and configured to receive a portion of the sensormodule, the housing includes a first portion defining a first open end,a second portion opposite the first end, and a lumen there through, thefirst portion being sized to be at least partially implanted within thewall of the blood vessel, the platform defines a recess around theaperture, and the second portion of the housing is sized to be receivedwithin the recess, and when the second portion of the housing isreceived within the recess, the second portion and the platform aresubstantially co-planar; and a plurality of connected and spaced apartlinks coupled to the sensor mounting, the plurality of connected andspaced apart links being configured to wrap around the blood vessel tomaintain the position of the sensor module with respect to the bloodvessel during pulsatile movements of the blood vessel, the plurality ofconnected and spaced apart links include a first end link and a secondlink, the sensor mounting includes a first side and a second sideopposite the first side, the first end link is configured to couple tothe first side of the sensor mounting and the second end link isconfigured to couple to the second side of the sensor mounting, each ofthe links in the plurality of connected and spaced apart links beingsubstantially evenly spaced, the plurality of spaced apart including atleast on strip molded through each of the plurality of connected andspaced apart links and configured to connect the plurality of connectedand spaced apart links together.